European patent 431669 discloses a method for manufacturing an object from a thermoplastic sandwich material, in which the normals of at least two surfaces of this object form an angle with respect to one another. This known method comprises at least the steps of softening a part of one of the surfaces of the thermoplastic sandwich material over a distance which corresponds to at least the length of an imaginary folding line of the angle between the two surfaces with the aid of a stamp, in which the stamp is at least partially pressed into the top layer of the thermoplastic sandwich material, and of folding the two surfaces of the thermoplastic material about the folding line, in such a manner that the surface which has been softened thus comes to lie on the inside of the angle.
By means of this method, an object with two surfaces at an angle to one another is produced, in which the excess material of the softened top layer of the sandwich material is present on the inside of the angle, and is melted in the foam core in the folded state. Thus, the excess material is prevented from bulging outwards, which could result in an unsatisfactory fold or angle.
WO 01/56780 describes a method and device for closing and finishing an open end of a panel, which usually comprises a set of thermoplastic cover layers or skins arranged at a distance from one another, which are connected to one another by ribs which extend in the length direction. A panel of this type thus comprises chambers through which a desired material may flow. With this known method, a projecting part of one of the cover layers is folded towards the other cover layer and connected thereto, for example by means of hot-welding, etc.
In the field, there is a general need for deforming methods for usually flat composite construction elements, such as sandwich panels, in which the positions of deformation are reinforced. More particularly, there is a need for such elements that have surfaces which are at an angle to one another, in which the angle is reinforced further. In a similar manner, there is also a need in the field for such elements with edges which have been reinforced. There is also a need to prevent the use of inserts in such panels, especially along the edges.